In Moscow, it comes down to a face-off between two ballroom-dance style programs, the Canadian's Samba and the American's Argentine Tango.

On paper, the U.S. champions look like good bets. The Canadians, who withdrew from their Grand Prix events after Virtue underwent surgery in October to relieve exertional compartment syndrome in her calves, have yet to finish a competition this season.

Meanwhile, Davis and White have won their two Grand Prix events; their second successive Grand Prix Final; and their third consecutive U.S. title.

At the 2011 ISU Four Continents Championships in February, the Americans lost a close decision in the short dance to the Canadians, but won the event after Virtue and Moir withdrew during their free dance, citing an injury to Virtue's thigh.

"Tessa is one hundred percent now, according to her doctors," Igor Shpilband, who with Marina Zoueva coaches both teams in Canton, Mich., said.

Arriving in Moscow, Moir remarked to reporters they could call the Canadians underdogs, despite the cache of the Olympic title.

"I would say that whatever you need to say to yourself, to get yourself motivated, is fine," White said. "Coming in here, I would say we're pretty even. Our scores are always close. We've been neck and neck, one competition to the next.

"It really comes down to how we skate, how we lay it out on the ice."

Shpilband thinks it's just too close to call.

"I think they have completely different programs, both are strong, it will just be very exciting to see," he said.

"Meryl and Charlie beat Tessa and Scott at last season's Grand Prix Final, and even though they lost to them at the Olympics, Meryl and Charlie won the free dance. They are close to each other, especially this year. Meryl and Charlie have done a lot of competitions and they are motivated to win the first U.S. world title."

Like White, Shpilband said it will likely all come down to which couple performs the better free dance. Even then, though, he's not sure what will happen.

"The thing that matters is the performances. Of course I want both teams skate their absolute best, that is my job," he said.

"But even if both performances are clean, then you have the judges' opinions. You cannot predict anything."